Heat sink



FIG. 1 is a perspective view of a heat sink showing a first embodimentour new design;

FIG. 2 is a left side elevational view thereof, the right sideelevational view being a mirror image thereof;

FIG. 3 is a front elevational view thereof, the rear elevational viewbeing a mirror image thereof;

FIG. 4 is a top plan view thereof; and,

FIG. 5 is a bottom plan view thereof.

The broken lines in the figure descriptions represent unclaimed subjectmatter and form no part of the claimed design.

CLAIM The ornamental design for a heat sink, as shown and described.